The problem is that current money is jumping from 0 to say 30. So if you want to buy a unit that costs 25 or 30 you can wait a little, the resourses will become 30 at a moment you buy it and it tries to take its money (taxes ) but they are gone.
1 min.: Income: +5
1 min. 10 secs: Income: +5
1 min. 20 secs: Income: +5
1 min. 29 secs: You buy unit for 25.
If you miss that in that moment at the next moment:
1 min. 30 secs: Outcome -20. You can't buy anything.
It is RTS, yes. +10 is per farm but in a moment when there are few farms and resourse collecting units and all they are upgraded that is a huge income. Even if they are not upgraded money is too much. The idea is to produce, later upgrade and keep all units not constantly producing and loosing. Which means if there are too much resourses you could make super army at any moment, if there are very low and you loose the army it is done. But the player has some heavy and expensive units and the game has not typical upgrades timeline, you can build such units instead of many cheap and I want with them built to have less money. It doesn't happen, I can take more territory and then more income and the AI is screwed.
Incomes are limited by the number of storages, so yes, resourses over the current limit are lost. Also outcomes are from repairing, building and shooting. No money - no shooting.
So you have to cheat actually because your base can't collect these taxes. And because there are irregular income it becomes worse. I havent enough time to test it fully yesterday but I think it works (the method above).
I am not sure I understand your proposal